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Groups > linux.kernel > #1399630 > unrolled thread

[PATCH] usb: ohci-at91: Suspend the ports while USB suspending

Started byWenyou Yang <wenyou.yang@atmel.com>
First post2016-05-12 03:20 +0200
Last post2016-05-13 03:40 +0200
Articles 5 — 4 participants

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Contents

  [PATCH] usb: ohci-at91: Suspend the ports while USB suspending Wenyou Yang <wenyou.yang@atmel.com> - 2016-05-12 03:20 +0200
    Re: [PATCH] usb: ohci-at91: Suspend the ports while USB suspending Alexandre Belloni <alexandre.belloni@free-electrons.com> - 2016-05-12 06:00 +0200
      RE: [PATCH] usb: ohci-at91: Suspend the ports while USB suspending "Yang, Wenyou" <Wenyou.Yang@atmel.com> - 2016-05-12 08:00 +0200
    Re: [PATCH] usb: ohci-at91: Suspend the ports while USB suspending Alan Stern <stern@rowland.harvard.edu> - 2016-05-12 20:20 +0200
      RE: [PATCH] usb: ohci-at91: Suspend the ports while USB suspending "Yang, Wenyou" <Wenyou.Yang@atmel.com> - 2016-05-13 03:40 +0200

#1399630 — [PATCH] usb: ohci-at91: Suspend the ports while USB suspending

FromWenyou Yang <wenyou.yang@atmel.com>
Date2016-05-12 03:20 +0200
Subject[PATCH] usb: ohci-at91: Suspend the ports while USB suspending
Message-ID<rxNsd-3dK-7@gated-at.bofh.it>
In order to get lower consumption, as a workaround, suspend
the USB PORTA/B/C via set the SUSPEND_A/B/C bits of OHCI Interrupt
Configuration Register while OHCI USB suspending.

This suspend operation must be done before stopping the USB clock,
resume after the USB clock enabled.

Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
---

 drivers/usb/host/ohci-at91.c | 63 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 63 insertions(+)

diff --git a/drivers/usb/host/ohci-at91.c b/drivers/usb/host/ohci-at91.c
index d177372..ce898e0 100644
--- a/drivers/usb/host/ohci-at91.c
+++ b/drivers/usb/host/ohci-at91.c
@@ -21,6 +21,8 @@
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
+#include <linux/mfd/syscon.h>
+#include <linux/regmap.h>
 #include <linux/usb.h>
 #include <linux/usb/hcd.h>
 
@@ -51,6 +53,7 @@ struct ohci_at91_priv {
 	struct clk *hclk;
 	bool clocked;
 	bool wakeup;		/* Saved wake-up state for resume */
+	struct regmap *sfr_regmap;
 };
 /* interface and function clocks; sometimes also an AHB clock */
 
@@ -132,6 +135,17 @@ static void at91_stop_hc(struct platform_device *pdev)
 
 /*-------------------------------------------------------------------------*/
 
+struct regmap *at91_dt_syscon_sfr(void)
+{
+	struct regmap *regmap;
+
+	regmap = syscon_regmap_lookup_by_compatible("atmel,sama5d2-sfr");
+	if (IS_ERR(regmap))
+		return NULL;
+
+	return regmap;
+}
+
 static void usb_hcd_at91_remove (struct usb_hcd *, struct platform_device *);
 
 /* configure so an HC device and id are always provided */
@@ -197,6 +211,8 @@ static int usb_hcd_at91_probe(const struct hc_driver *driver,
 		goto err;
 	}
 
+	ohci_at91->sfr_regmap = at91_dt_syscon_sfr();
+
 	board = hcd->self.controller->platform_data;
 	ohci = hcd_to_ohci(hcd);
 	ohci->num_ports = board->ports;
@@ -581,6 +597,49 @@ static int ohci_hcd_at91_drv_remove(struct platform_device *pdev)
 	return 0;
 }
 
+#define SFR_OHCIICR		0x10
+#define SFR_OHCIICR_SUSPEND_A	BIT(8)
+#define SFR_OHCIICR_SUSPEND_B	BIT(9)
+#define SFR_OHCIICR_SUSPEND_C	BIT(10)
+
+#define SFR_OHCIICR_USB_SUSPEND	(SFR_OHCIICR_SUSPEND_A | \
+				 SFR_OHCIICR_SUSPEND_B | \
+				 SFR_OHCIICR_SUSPEND_C)
+
+static int ohci_at91_port_ctrl(struct regmap *regmap, bool enable)
+{
+	u32 regval;
+	int ret;
+
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+
+	ret = regmap_read(regmap, SFR_OHCIICR, &regval);
+	if (ret)
+		return ret;
+
+	if (enable)
+		regval &= ~SFR_OHCIICR_USB_SUSPEND;
+	else
+		regval |= SFR_OHCIICR_USB_SUSPEND;
+
+	regmap_write(regmap, SFR_OHCIICR, regval);
+
+	regmap_read(regmap, SFR_OHCIICR, &regval);
+
+	return 0;
+}
+
+static int ohci_at91_port_suspend(struct regmap *regmap)
+{
+	return ohci_at91_port_ctrl(regmap, false);
+}
+
+static int ohci_at91_port_resume(struct regmap *regmap)
+{
+	return ohci_at91_port_ctrl(regmap, true);
+}
+
 static int __maybe_unused
 ohci_hcd_at91_drv_suspend(struct device *dev)
 {
@@ -618,6 +677,8 @@ ohci_hcd_at91_drv_suspend(struct device *dev)
 		ohci_writel(ohci, ohci->hc_control, &ohci->regs->control);
 		ohci->rh_state = OHCI_RH_HALTED;
 
+		ohci_at91_port_suspend(ohci_at91->sfr_regmap);
+
 		/* flush the writes */
 		(void) ohci_readl (ohci, &ohci->regs->control);
 		at91_stop_clock(ohci_at91);
@@ -637,6 +698,8 @@ ohci_hcd_at91_drv_resume(struct device *dev)
 
 	at91_start_clock(ohci_at91);
 
+	ohci_at91_port_resume(ohci_at91->sfr_regmap);
+
 	ohci_resume(hcd, false);
 	return 0;
 }
-- 
2.7.4

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#1399659

FromAlexandre Belloni <alexandre.belloni@free-electrons.com>
Date2016-05-12 06:00 +0200
Message-ID<rxPX3-5E8-1@gated-at.bofh.it>
In reply to#1399630
Hi,

On 12/05/2016 at 09:05:34 +0800, Wenyou Yang wrote :
> In order to get lower consumption, as a workaround, suspend
> the USB PORTA/B/C via set the SUSPEND_A/B/C bits of OHCI Interrupt
> Configuration Register while OHCI USB suspending.
> 

Why is that a workaround?

> This suspend operation must be done before stopping the USB clock,
> resume after the USB clock enabled.
> 
> Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
> ---
> 
>  drivers/usb/host/ohci-at91.c | 63 ++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 63 insertions(+)
> 
> diff --git a/drivers/usb/host/ohci-at91.c b/drivers/usb/host/ohci-at91.c
> index d177372..ce898e0 100644
> --- a/drivers/usb/host/ohci-at91.c
> +++ b/drivers/usb/host/ohci-at91.c
> @@ -21,6 +21,8 @@
>  #include <linux/io.h>
>  #include <linux/kernel.h>
>  #include <linux/module.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/regmap.h>
>  #include <linux/usb.h>
>  #include <linux/usb/hcd.h>
>  
> @@ -51,6 +53,7 @@ struct ohci_at91_priv {
>  	struct clk *hclk;
>  	bool clocked;
>  	bool wakeup;		/* Saved wake-up state for resume */
> +	struct regmap *sfr_regmap;
>  };
>  /* interface and function clocks; sometimes also an AHB clock */
>  
> @@ -132,6 +135,17 @@ static void at91_stop_hc(struct platform_device *pdev)
>  
>  /*-------------------------------------------------------------------------*/
>  
> +struct regmap *at91_dt_syscon_sfr(void)
> +{
> +	struct regmap *regmap;
> +
> +	regmap = syscon_regmap_lookup_by_compatible("atmel,sama5d2-sfr");
> +	if (IS_ERR(regmap))
> +		return NULL;
> +
> +	return regmap;
> +}
> +
>  static void usb_hcd_at91_remove (struct usb_hcd *, struct platform_device *);
>  
>  /* configure so an HC device and id are always provided */
> @@ -197,6 +211,8 @@ static int usb_hcd_at91_probe(const struct hc_driver *driver,
>  		goto err;
>  	}
>  
> +	ohci_at91->sfr_regmap = at91_dt_syscon_sfr();
> +
>  	board = hcd->self.controller->platform_data;
>  	ohci = hcd_to_ohci(hcd);
>  	ohci->num_ports = board->ports;
> @@ -581,6 +597,49 @@ static int ohci_hcd_at91_drv_remove(struct platform_device *pdev)
>  	return 0;
>  }
>  
> +#define SFR_OHCIICR		0x10
> +#define SFR_OHCIICR_SUSPEND_A	BIT(8)
> +#define SFR_OHCIICR_SUSPEND_B	BIT(9)
> +#define SFR_OHCIICR_SUSPEND_C	BIT(10)
> +
> +#define SFR_OHCIICR_USB_SUSPEND	(SFR_OHCIICR_SUSPEND_A | \
> +				 SFR_OHCIICR_SUSPEND_B | \
> +				 SFR_OHCIICR_SUSPEND_C)
> +

Those defines should go in a header file either in include/soc/at91 or
in include/linux/mfd

> +static int ohci_at91_port_ctrl(struct regmap *regmap, bool enable)
> +{
> +	u32 regval;
> +	int ret;
> +
> +	if (IS_ERR(regmap))
> +		return PTR_ERR(regmap);
> +
> +	ret = regmap_read(regmap, SFR_OHCIICR, &regval);
> +	if (ret)
> +		return ret;
> +
> +	if (enable)
> +		regval &= ~SFR_OHCIICR_USB_SUSPEND;
> +	else
> +		regval |= SFR_OHCIICR_USB_SUSPEND;
> +
> +	regmap_write(regmap, SFR_OHCIICR, regval);
> +
> +	regmap_read(regmap, SFR_OHCIICR, &regval);
> +
> +	return 0;
> +}
> +
> +static int ohci_at91_port_suspend(struct regmap *regmap)
> +{
> +	return ohci_at91_port_ctrl(regmap, false);
> +}
> +
> +static int ohci_at91_port_resume(struct regmap *regmap)
> +{
> +	return ohci_at91_port_ctrl(regmap, true);
> +}
> +
>  static int __maybe_unused
>  ohci_hcd_at91_drv_suspend(struct device *dev)
>  {
> @@ -618,6 +677,8 @@ ohci_hcd_at91_drv_suspend(struct device *dev)
>  		ohci_writel(ohci, ohci->hc_control, &ohci->regs->control);
>  		ohci->rh_state = OHCI_RH_HALTED;
>  
> +		ohci_at91_port_suspend(ohci_at91->sfr_regmap);
> +

The main issue I see here is that you will call that function for all
SoCs and it will always fail unless it is running on a sama5d2. Maybe we
could be smarter about that.


-- 
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

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#1399677

From"Yang, Wenyou" <Wenyou.Yang@atmel.com>
Date2016-05-12 08:00 +0200
Message-ID<rxRPc-7Th-1@gated-at.bofh.it>
In reply to#1399659

> -----Original Message-----
> From: Alexandre Belloni [mailto:alexandre.belloni@free-electrons.com]
> Sent: 2016年5月12日 11:53
> To: Yang, Wenyou <Wenyou.Yang@atmel.com>
> Cc: Alan Stern <stern@rowland.harvard.edu>; Greg Kroah-Hartman
> <gregkh@linuxfoundation.org>; Ferre, Nicolas <Nicolas.FERRE@atmel.com>;
> linux-usb@vger.kernel.org; linux-kernel@vger.kernel.org; linux-arm-
> kernel@lists.infradead.org
> Subject: Re: [PATCH] usb: ohci-at91: Suspend the ports while USB suspending
> 
> Hi,
> 
> On 12/05/2016 at 09:05:34 +0800, Wenyou Yang wrote :
> > In order to get lower consumption, as a workaround, suspend the USB
> > PORTA/B/C via set the SUSPEND_A/B/C bits of OHCI Interrupt
> > Configuration Register while OHCI USB suspending.
> >
> 
> Why is that a workaround?

Because if these bits is not set as this patch, there is 5mA current left
at VDDOSC rail during suspend. If apply this patch, this current will disappear.

So, I think it is a workaround.

> 
> > This suspend operation must be done before stopping the USB clock,
> > resume after the USB clock enabled.
> >
> > Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
> > ---
> >
> >  drivers/usb/host/ohci-at91.c | 63
> > ++++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 63 insertions(+)
> >
> > diff --git a/drivers/usb/host/ohci-at91.c
> > b/drivers/usb/host/ohci-at91.c index d177372..ce898e0 100644
> > --- a/drivers/usb/host/ohci-at91.c
> > +++ b/drivers/usb/host/ohci-at91.c
> > @@ -21,6 +21,8 @@
> >  #include <linux/io.h>
> >  #include <linux/kernel.h>
> >  #include <linux/module.h>
> > +#include <linux/mfd/syscon.h>
> > +#include <linux/regmap.h>
> >  #include <linux/usb.h>
> >  #include <linux/usb/hcd.h>
> >
> > @@ -51,6 +53,7 @@ struct ohci_at91_priv {
> >  	struct clk *hclk;
> >  	bool clocked;
> >  	bool wakeup;		/* Saved wake-up state for resume */
> > +	struct regmap *sfr_regmap;
> >  };
> >  /* interface and function clocks; sometimes also an AHB clock */
> >
> > @@ -132,6 +135,17 @@ static void at91_stop_hc(struct platform_device
> > *pdev)
> >
> >
> > /*--------------------------------------------------------------------
> > -----*/
> >
> > +struct regmap *at91_dt_syscon_sfr(void) {
> > +	struct regmap *regmap;
> > +
> > +	regmap = syscon_regmap_lookup_by_compatible("atmel,sama5d2-sfr");
> > +	if (IS_ERR(regmap))
> > +		return NULL;
> > +
> > +	return regmap;
> > +}
> > +
> >  static void usb_hcd_at91_remove (struct usb_hcd *, struct
> > platform_device *);
> >
> >  /* configure so an HC device and id are always provided */ @@ -197,6
> > +211,8 @@ static int usb_hcd_at91_probe(const struct hc_driver *driver,
> >  		goto err;
> >  	}
> >
> > +	ohci_at91->sfr_regmap = at91_dt_syscon_sfr();
> > +
> >  	board = hcd->self.controller->platform_data;
> >  	ohci = hcd_to_ohci(hcd);
> >  	ohci->num_ports = board->ports;
> > @@ -581,6 +597,49 @@ static int ohci_hcd_at91_drv_remove(struct
> platform_device *pdev)
> >  	return 0;
> >  }
> >
> > +#define SFR_OHCIICR		0x10
> > +#define SFR_OHCIICR_SUSPEND_A	BIT(8)
> > +#define SFR_OHCIICR_SUSPEND_B	BIT(9)
> > +#define SFR_OHCIICR_SUSPEND_C	BIT(10)
> > +
> > +#define SFR_OHCIICR_USB_SUSPEND	(SFR_OHCIICR_SUSPEND_A | \
> > +				 SFR_OHCIICR_SUSPEND_B | \
> > +				 SFR_OHCIICR_SUSPEND_C)
> > +
> 
> Those defines should go in a header file either in include/soc/at91 or in
> include/linux/mfd
> 
> > +static int ohci_at91_port_ctrl(struct regmap *regmap, bool enable) {
> > +	u32 regval;
> > +	int ret;
> > +
> > +	if (IS_ERR(regmap))
> > +		return PTR_ERR(regmap);
> > +
> > +	ret = regmap_read(regmap, SFR_OHCIICR, &regval);
> > +	if (ret)
> > +		return ret;
> > +
> > +	if (enable)
> > +		regval &= ~SFR_OHCIICR_USB_SUSPEND;
> > +	else
> > +		regval |= SFR_OHCIICR_USB_SUSPEND;
> > +
> > +	regmap_write(regmap, SFR_OHCIICR, regval);
> > +
> > +	regmap_read(regmap, SFR_OHCIICR, &regval);
> > +
> > +	return 0;
> > +}
> > +
> > +static int ohci_at91_port_suspend(struct regmap *regmap) {
> > +	return ohci_at91_port_ctrl(regmap, false); }
> > +
> > +static int ohci_at91_port_resume(struct regmap *regmap) {
> > +	return ohci_at91_port_ctrl(regmap, true); }
> > +
> >  static int __maybe_unused
> >  ohci_hcd_at91_drv_suspend(struct device *dev)  { @@ -618,6 +677,8 @@
> > ohci_hcd_at91_drv_suspend(struct device *dev)
> >  		ohci_writel(ohci, ohci->hc_control, &ohci->regs->control);
> >  		ohci->rh_state = OHCI_RH_HALTED;
> >
> > +		ohci_at91_port_suspend(ohci_at91->sfr_regmap);
> > +
> 
> The main issue I see here is that you will call that function for all SoCs and it will
> always fail unless it is running on a sama5d2. Maybe we could be smarter about
> that.

Can we use another compatible, such as "atmel,sama5d2-ohci" to differentiate it? 


Best Regards,
Wenyou Yang

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#1400274

FromAlan Stern <stern@rowland.harvard.edu>
Date2016-05-12 20:20 +0200
Message-ID<ry3nj-2Jt-9@gated-at.bofh.it>
In reply to#1399630
On Thu, 12 May 2016, Wenyou Yang wrote:

> In order to get lower consumption, as a workaround, suspend
> the USB PORTA/B/C via set the SUSPEND_A/B/C bits of OHCI Interrupt
> Configuration Register while OHCI USB suspending.

What does this mean?  What does suspending a port do?  Is it the same 
as a normal USB port suspend?

If it is the same, why doesn't the USB_PORT_FEAT_SUSPEND subcase of the 
SetPortFeature case in ohci_hub_control() already take care of this?

> This suspend operation must be done before stopping the USB clock,
> resume after the USB clock enabled.
> 
> Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
> ---

> @@ -132,6 +135,17 @@ static void at91_stop_hc(struct platform_device *pdev)
>  
>  /*-------------------------------------------------------------------------*/
>  
> +struct regmap *at91_dt_syscon_sfr(void)
> +{
> +	struct regmap *regmap;
> +
> +	regmap = syscon_regmap_lookup_by_compatible("atmel,sama5d2-sfr");
> +	if (IS_ERR(regmap))
> +		return NULL;

If you get an error, the regmap pointer is set to NULL...

> @@ -197,6 +211,8 @@ static int usb_hcd_at91_probe(const struct hc_driver *driver,
>  		goto err;
>  	}
>  
> +	ohci_at91->sfr_regmap = at91_dt_syscon_sfr();

With no other error checking...

> +
>  	board = hcd->self.controller->platform_data;
>  	ohci = hcd_to_ohci(hcd);
>  	ohci->num_ports = board->ports;

> +static int ohci_at91_port_ctrl(struct regmap *regmap, bool enable)
> +{
> +	u32 regval;
> +	int ret;
> +
> +	if (IS_ERR(regmap))
> +		return PTR_ERR(regmap);
> +
> +	ret = regmap_read(regmap, SFR_OHCIICR, &regval);

And now what happens if regmap is NULL?  Hint: It won't be pretty...

Alan Stern

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#1400441

From"Yang, Wenyou" <Wenyou.Yang@atmel.com>
Date2016-05-13 03:40 +0200
Message-ID<ryaf8-1gh-1@gated-at.bofh.it>
In reply to#1400274
Hi Alan,

> -----Original Message-----
> From: Alan Stern [mailto:stern@rowland.harvard.edu]
> Sent: 2016年5月13日 2:11
> To: Yang, Wenyou <Wenyou.Yang@atmel.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>; Ferre, Nicolas
> <Nicolas.FERRE@atmel.com>; linux-usb@vger.kernel.org; linux-
> kernel@vger.kernel.org; linux-arm-kernel@lists.infradead.org
> Subject: Re: [PATCH] usb: ohci-at91: Suspend the ports while USB suspending
> 
> On Thu, 12 May 2016, Wenyou Yang wrote:
> 
> > In order to get lower consumption, as a workaround, suspend the USB
> > PORTA/B/C via set the SUSPEND_A/B/C bits of OHCI Interrupt
> > Configuration Register while OHCI USB suspending.
> 
> What does this mean?  What does suspending a port do?  

It is a IP workaround for SAMA5D2 USB. By setting corresponding bits of a specific register to get lower consumption.  

> Is it the same as a normal USB port suspend?

No, it is not same.

> 
> If it is the same, why doesn't the USB_PORT_FEAT_SUSPEND subcase of the
> SetPortFeature case in ohci_hub_control() already take care of this?
> 
> > This suspend operation must be done before stopping the USB clock,
> > resume after the USB clock enabled.
> >
> > Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
> > ---
> 
> > @@ -132,6 +135,17 @@ static void at91_stop_hc(struct platform_device
> > *pdev)
> >
> >
> > /*--------------------------------------------------------------------
> > -----*/
> >
> > +struct regmap *at91_dt_syscon_sfr(void) {
> > +	struct regmap *regmap;
> > +
> > +	regmap = syscon_regmap_lookup_by_compatible("atmel,sama5d2-sfr");
> > +	if (IS_ERR(regmap))
> > +		return NULL;
> 
> If you get an error, the regmap pointer is set to NULL...
> 
> > @@ -197,6 +211,8 @@ static int usb_hcd_at91_probe(const struct hc_driver
> *driver,
> >  		goto err;
> >  	}
> >
> > +	ohci_at91->sfr_regmap = at91_dt_syscon_sfr();
> 
> With no other error checking...

Add error checking in next version.

> 
> > +
> >  	board = hcd->self.controller->platform_data;
> >  	ohci = hcd_to_ohci(hcd);
> >  	ohci->num_ports = board->ports;
> 
> > +static int ohci_at91_port_ctrl(struct regmap *regmap, bool enable) {
> > +	u32 regval;
> > +	int ret;
> > +
> > +	if (IS_ERR(regmap))
> > +		return PTR_ERR(regmap);
> > +
> > +	ret = regmap_read(regmap, SFR_OHCIICR, &regval);
> 
> And now what happens if regmap is NULL?  Hint: It won't be pretty...

Yes, it is not pretty. Will rework in next version.

> 
> Alan Stern


Best Regards,
Wenyou Yang

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